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Re: Topband: Another Spitfire question

To: "bruce whitney" <zuceman@yahoo.com>, "Eduardo Araujo" <er_araujo@yahoo.com>, "Topband" <topband@contesting.com>
Subject: Re: Topband: Another Spitfire question
From: "Tom W8JI" <w8ji@w8ji.com>
Reply-to: Tom W8JI <w8ji@w8ji.com>
Date: Wed, 6 Nov 2013 13:54:29 -0500
List-post: <topband@contesting.com">mailto:topband@contesting.com>
How can I tune the parasitic elements (with an analyzer) when supported by a permanently grounded (shunt fed, Omega matched) tower?


You can't, at least not in a meaningful way.

I read the tuning procedure requiring the tower to be ungrounded? - non resonant, in order to set the length of the parasitics?>>>

Yes. That would have to be the case.

Also - with Tom's analysis, that the parasitics are actually sloped verticals - by virtue of the horizontal portion ground coupling - wouldn't one be better off stringing multiple (exactly opposite) counterpoise wires?>>>

It would make the array less sensitive to ground losses under the counterpoise.

Halfwave antennas are really only half wave antennas when they are reasonably straight. When we severely bend one and place the bent leg very near earth, it really becomes a Marconi with a counterpoise. The wire near earth is really just a single elevated radial, no matter what we want to call it.
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